Thyroid autoimmunity in insulin-dependent diabetes mellitus: the case for routine screening

Area of Science:

• Endocrinology
• Immunology
• Diabetology

Background:

• Autoimmune diseases frequently coexist in patients with Type 1 diabetes.
• Thyroid dysfunction is a common comorbidity in individuals with insulin-dependent diabetes mellitus (IDDM).

Purpose of the Study:

• To determine the prevalence of thyroid microsomal autoantibodies (TMA) in young patients with IDDM.
• To investigate the association between TMA and thyroid dysfunction (hyperthyroidism and hypothyroidism) in this population.
• To assess the frequency of other autoantibodies (gastric and adrenocortical) in IDDM patients with TMA.

Main Methods:

• Cross-sectional study of 771 young patients diagnosed with IDDM.
• Serological testing for thyroid microsomal autoantibodies (TMA) and thyroglobulin autoantibodies.
• Thyroid function tests (thyroid hormone levels) and autoantibody assessments for gastric parietal and adrenocortical antibodies were performed on a subset of patients.

Main Results:

• Thyroid microsomal autoantibodies (TMA) were detected in 17.6% of young IDDM patients, with a higher prevalence in white patients (20.1%) and females (nearly 2:1 ratio).
• Among 117 patients with TMA and evidence of chronic thyroiditis, 7% had hyperthyroidism and 38% had hypothyroidism.
• Gastric (16.8%) and adrenocortical (5.1%) autoantibodies were also found at increased frequencies in patients with TMA.

Conclusions:

• A significant proportion of young IDDM patients possess TMA, indicating an autoimmune link to thyroid disease.
• Routine screening for TMA in IDDM patients is warranted, followed by annual thyroid function monitoring.
• Co-occurrence of other autoantibodies suggests a broader autoimmune polyendocrine susceptibility in IDDM patients with TMA.